This invention relates to an apparatus and method for monitoring and controlling a heating and/or cooling system which controls the temperature of air in a conditioned space within a building or a commercial freezer or refrigeration unit. More particularly, this invention relates to such an apparatus and method capable of indicating the performance of such a system and effectuating control over the system for maximizing the operating performance of the system.
Most dwellings and commercial buildings now in use are serviced by systems for circulating a flow of air through the spaces within the building and controlling the temperature of the circulating flow of air. Such systems may use various means of heating and/or cooling the flow of air, including combustion of fuels, mechanical refrigeration systems circulating liquids, and dual cycle systems of the types known as heat pumps. Such systems conventionally have temperature sensors in the conditioned spaces for sensing air temperatures in those spaces (often known as thermostats) and control systems responsive to the temperature sensors for changing the temperature of flowing air to reach and maintain a desired temperature in the conditioned space.
It has been recognized heretofore that such systems may have varying performance, and that maintenance of satisfactory system performance (herein sometimes also referred to as operating efficiency) is beneficial in minimizing the costs of maintaining the desired temperature effects within a building. It has been proposed heretofore that certain additional temperature measurements may be used to monitor the operation of a system, or that system performance may be somewhat controlled by the provision of timing controls which govern the intervals of operation of a system. However, such proposals typically do not assure than an operator of a system be advised of the performance attained or not attained, in order that preventative maintenance be applied to sustain system performance.